34271-54-0Relevant articles and documents
Varietal Differences in the Total and Enantiomeric Composition of Theanine in Tea
Helen Ekborg-Ott,Taylor, Andre,Armstrong, Daniel W.
, p. 353 - 363 (1997)
Theanine is the main amino acid component in tea. It usually constitutes between 1 and 2% of the dry weight of the tea leaves. It is as prevalent in tea as all other free amino acids combined. Both enantiomers of theanine were found to have a similar sweet taste, with little or no aftertaste. It was found that black and half-green teas (except for Formosa Oolong) contained as much, or more, theanine as green teas. No correlation was found between the absolute concentration of theanine in tea and its enantiomeric composition. An inverse correlation was found between certain grades of tea (e.g., pekoe, Flowery Orange Pekoe, etc.) and the percent of D-theanine present. This could provide the basis for a reproducible, scientific method to grade and/or evaluate teas. Theanine slowly racemizes in aqueous solution. It also undergoes hydrolysis, particularly at basic pH values. By monitoring these processes, information may be gleaned on the production, storage, handling, and shipping of tea and tea products.
Preparation method of L-theanine
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, (2020/04/02)
The invention relates to the technical field of organic chemical synthesis, in particular to a preparation method of L-theanine. The preparation method of the L-theanine comprises the following steps:(a) reacting L-glutamic acid with a copper salt in a solvent to obtain a chelate A; (b) carrying out an esterification reaction on the chelate A and methanol to obtain a compound B; and (c) after a reaction of the compound B with an aqueous ethylamine solution is finished, adding a decoppering reagent, carrying out stirring for a reaction, and removing a solvent to obtain a crude L-theanine product. According to the preparation method of the L-theanine, the L-glutamic acid is used as an initial raw material and is easy to obtain; in addition, residues in amino acid are protected by adopting acopper chelate manner, so the reaction process is green and environment-friendly. In the step (c), the safer aqueous ethylamine solution is used for the reaction, so the safety of the reaction is improved, requirements on equipment are reduced, production cost is greatly saved, and industrial production is easier.
Characterization of l -Theanine Excitatory Actions on Hippocampal Neurons: Toward the Generation of Novel N-Methyl- d -aspartate Receptor Modulators Based on Its Backbone
Sebih, Fatiha,Rousset, Matthieu,Bellahouel, Salima,Rolland, Marc,De Jesus Ferreira, Marie Celeste,Guiramand, Janique,Cohen-Solal, Catherine,Barbanel, Gérard,Cens, Thierry,Abouazza, Mohammed,Tassou, Adrien,Gratuze, Maud,Meusnier, Céline,Charnet, Pierre,Vignes, Michel,Rolland, Valérie
, p. 1724 - 1734 (2017/08/21)
l-Theanine (or l-γ-N-ethyl-glutamine) is the major amino acid found in Camellia sinensis. It has received much attention because of its pleiotropic physiological and pharmacological activities leading to health benefits in humans, especially. We describe here a new, easy, efficient, and environmentally friendly chemical synthesis of l-theanine and l-γ-N-propyl-Gln and their corresponding d-isomers. l-Theanine, and its derivatives obtained so far, exhibited partial coagonistic action at N-methyl-d-aspartate (NMDA) receptors, with no detectable agonist effect at other glutamate receptors, on cultured hippocampal neurons. This activity was retained on NMDA receptors expressed in Xenopus oocytes. In addition, both GluN2A and GluN2B containing NMDA receptors were equally modulated by l-theanine. The stereochemical change from l-theanine to d-theanine along with the substitution of the ethyl for a propyl moiety in the γ-N position of l- and d-theanine significantly enhanced the biological efficacy, as measured on cultured hippocampal neurons. l-Theanine structure thus represents an interesting backbone to develop novel NMDA receptor modulators.
Synthesis of amino acid using a flow-type microreactor containing enzyme-mesoporous silica microsphere composites
Matsuura, Shun-Ichi,Chiba, Manami,Tomon, Emiko,Tsunoda, Tatsuo
, p. 9021 - 9030 (2014/03/21)
A flow-type microreactor containing composite materials of a theanine synthetase (glutaminase) and mesoporous silica with 23.6 nm pore diameter (SBA-15 microsphere) was developed for the continuous synthesis of l-theanine, a unique amino acid. Enzyme-immobilisation ability and enzymatic activity in the SBA-15 microsphere with large mesopores were higher than those of SBA-15 with a 5.4 nm pore diameter. Moreover, the glutaminase-SBA-15 microsphere composites displayed higher selectivity in theanine production than the free enzyme did in a batch experiment. A direct visualization of composites of fluorescently labelled glutaminase and SBA-15 microsphere immobilised in the flow channel of the microreactor by a combination of differential interference contrast and fluorescence microscopy revealed that the enzymes were uniformly dispersed throughout the mesoporous silica particles, because of the successful encapsulation of the enzyme. The enzyme-encapsulated microreactor exhibited a high conversion of l-glutamine to l-theanine with local control of the reaction temperature. In addition to this advantage of the microreaction system, the microreactor enabled the on-off regulation of enzymatic activity during continuous theanine synthesis by controlling the reaction temperature or the pH of the substrate solution.
